Outdoor Pond Ideas: Pond in a Box

Build this simple, above-ground pond in a weekend. It features a fountain and a trellis. It's attractive, yet you avoid the tough digging chore. Plus it's less of a hazard for toddlers than an in-ground pond.

Overview: Pond design and costs

Lion's head fountain

Fountain prices range from $25 to over $1,000.

Ponds don't necessarily have to be in the ground. By
adopting some of the techniques and materials used in
the wood foundation industry, you can build a pond
above ground a whole lot faster and easier. An above-ground
design may be safer, too, but always supervise small children
around any type of pond.

In this story, we'll show you all the steps you'll need to build
your own version. We built the pond with treated wood for
longevity and used rough-sawn cedar for the trim and the trellis.
But if cedar isn't available, you can use any weather-resistant material including treated wood,
cement board siding, vinyl, composite wood
or any mix of these in your area. You can
make your pond longer or wider (stay
under 6 ft. long on either wall), but don't
make it any deeper or the walls may
bow. You'll only need a circular saw to
build your pond plus the usual carpentry
hand tools, but a miter saw makes
faster, more accurate cuts. You'll need a
jigsaw to cut the curved trellis parts.

Expect to spend about $300 for the
box and trellis materials, $80 for the liner
and another $75 for the pump. Fountain
“masks” can range in cost from $25 for small
plastic ones to $1,500 for elaborate bronze or
lead casts. The fiberglass lion's head shown cost
about $120.

Special Above-Ground Pond Advantages

NO-DIG: With this design, there's
practically none of the worst part of
pond building—gut-busting digging.
And that also means there's no
huge pile of dirt to get rid of.

FAST: Talk about instant gratification!
Build the walls and trellis in
the morning and assemble the
pond in the afternoon. Add the trim
the next day and go buy goldfish!

SAFER: Traditional in-ground
ponds can be a drowning hazard
for toddlers and pets. With this
above-ground design, the risk
is reduced.

Step 1: Pick a spot and buy the materials

You can position your pond just about anywhere you want,
including on a slope. Of course, that'll mean extra digging. If you
nest it into a hill, just backfill against the walls after the pond is
filled. Sunny areas will promote algae growth, so site your pond
in the shade if you want to reduce cleaning chores. We didn't
include a filter, but consider adding one if you'd like consistently
clear water. If you want a water-spewing fountain mask, you'll
need a pump and a power supply. So locating your pond as close
as possible to a power source will eliminate a lot of trenching
and running underground cable, and you won't have to add a
waterproof outlet. (For more information type “underground wiring” into the search box above.) If you're
placing the pond against a wall, keep it at least 2 ft. away so you
can access the back for hookups and maintenance.

Buying the materials
You'll find everything you need at any home center
(see Materials List below). If there isn't a dedicated
section for pond supplies, go to a garden
center for those materials. Pond liner is sold
in precut boxed kits or cut from 12-ft.-wide
bulk rolls, which generally costs less. Get a
10-ft. length or an equivalent-sized kit.
Also buy the same length of pond cushion.
That protects the liner from punctures.
To save money, you can substitute a
few layers of landscaping fabric for the
pad like we did (the home center was out
of liner pad) or even use old carpeting.
If you'd like a fountain mask, you can prowl
garden centers that have well-stocked pond
departments. Or go online and do a search for
“pond fountain head mask”—you'll find dozens to
choose from. Choosing a fiberglass mask makes the
most sense. They're light and easy to mount. Because masks of
cast metal or concrete are very heavy, they cost more to ship and
are difficult to mount. Masks may or may not have mounting
holes or hardware. So be prepared to drill your own holes and
figure out how to fasten it to the arbor. We drilled two holes in
a few mane crevices and used deck screws to hold ours in place.
You'll also need a pump and 10 ft. of water line and whatever
hardware is necessary to connect it at both ends.

Pond Details

Figures A and B, and a Cutting List and a Materials List are available in pdf format in Additional Information below.

Step 2: Construct the walls and trellis

Photo 1: Build the walls and trellis

Build the walls and trellis on a big, flat work surface like
your driveway. Mount the trellis on the back wall before
moving it to the pond site.

First cut the footing plates to length and then cut the parts and
build the walls (Figure A). Be sure to choose nails that are rated
for treated wood or your pond won't last more than a few years.
Leave out the corner backer boards for now so you can screw the
walls to the footing plates at the corners once the walls are
installed (Photo 4). Don't forget to screw two 2x4 trellis ledgers
to the rear wall with GRK screws (or substitute 3-in. deck
screws).

Build the trellis next (Photo 1). It's up to you which way the
trellis faces; it has two distinct sides. (If you look closely, you'll
see we changed our mind halfway through and flipped it
around.) To cut the arched rail, first cut the 2x6 to length and
then mark the measurements we show on Figure A. For the end
curves, line a 5-gallon bucket up with the marks and trace
around it. For the center curve, bend a thin flexible board or
steel rule to the marks and have someone trace along it while
you hold it. Cut the three curves with a jigsaw.

Step 3: Assemble the walls

Photo 2: Level the footings

Level the concrete pads that support the pond box corners.
Fill the trenches between the pads with gravel.

Photo 3: Set the footing plates

Toe-screw the footing plate together at the corners to
form a level platform for the walls.

Photo 4: Erect the walls

Lock the walls together by screwing them to each other
and then to the footing plates. Add overlapping tie plates
for rock-solid corners.

Lay the footing plates on the ground to
finalize the pond's location and then lay
out the footings. Mark the ground 6 in. on
both sides of the plates with marking
paint and dig a 4-in.-deep trench on all
four sides. Keep the bottoms reasonably
level, but don't beat yourself up over it.
Try to stay within an inch or so of level.

Spread about 3 in. of gravel at the
trench corners and set the steppingstones,
again using the footing plates in
their final positions to help with exact
placement. Adjust them until they're all
level with one another. Use a straight footing
plate to extend your level wherever
you need it (Photo 2). Finish filling
between the stepping-stones so the gravel
is level with the tops. Last, reset the footing
plates and toe-screw them together
(Photo 3).

Note that the walls overlap the footing
plates. The water pressure inside the walls
is no small force, so it's important that
everything be tied together. Screw together
the wall corners and check to make sure
the pond is square before screwing the
corners to the footing plates (Photo 4).
Then screw or nail the corner backer
boards in place. Overlap the top plates to
tie the wall corners together.

Step 4: Install the pond liner

Photo 5: Eliminate sharp corners

Eliminate sharp corners inside the box to prevent stress
on the liner. Fill inside corners with 45-degree strips and
slope sand up against the walls.

Photo 6: Add a liner pad

Line the box with padding to protect the liner. Pull any
protruding staples with a hammer to prevent punctures.

Photo 7: Install the liner

Work on the pleats and smooth creases in the liner as
you fill the pond. Add the liner clamp boards and trim off
the excess liner.

Rip 45-degree corner blocks and tack
them to the inside corners to help protect
the pond liner. Spread a 2-in. layer of sand
on the bottom of the pond to protect the
liner and mound up sand against the walls
to eliminate any sharp corners (Photo 5).
Both of these steps prevent stress on the
liner. Staple the liner pad to the walls
(Photo 6). Be sure to set all the staples or
pull mis-set ones so none of them will poke
holes in the liner. Trim off the liner even
with the top with a scissors.

Lay and center the liner inside the walls,
pleating the corners to avoid creating a
thick lump of fabric. Then begin filling
the pond. As water runs in, it'll force the
liner against the walls and the bottom to
eliminate voids. As the pond fills, continually
work on the pleats and smooth out
the sides to keep the liner as wrinkle free
as possible (Photo 7). It'll get harder and
harder to work the liner as the pond fills,
so keep at it throughout the fill. When
you're satisfied, cut and install the 1x4
liner clamp board. Screw, rather than nail,
the clamp board to make it easier to
replace the liner later. Leave a small gap in
front of the trellis to feed the water line
and cord through (Figure A). Then trim
off the excess liner with a utility knife.

Step 5: Add trim, side walls and a finish

Photo 8: Nail on trim and siding

Nail on the backfill boards and cap them with Z-flashing.
Then add the corner boards, frieze boards, and finally
the siding and top caps.

Cut the backfill boards to fit, then rest
them on the footing plate and nail them to
each stud. Cap them with Z-flashing to
divert water. Add the cedar corner boards.
It looks best to rip one side of each corner
so the total width will be the same on each
side. Add the 2x2 frieze board between the
corner boards at the top of the walls and
then nail on the siding (Photo 8). Lay out
the siding so the exposure is equal on all
the pieces. Lastly, add the 2x10 top caps.
Before cutting them to length, test-fit the
pieces to make sure the overhangs will be
equal everywhere. The top cap against the
trellis won't be exactly centered; it'll
extend a bit farther over the pond. But
that won't be noticeable. Don’t miter the
top cap corners; instead, use butt joints
as we did. Miters will open up in a very
short time.

After going through the tedious process
of staining the finished product with a
latex-based exterior wood stain, we
recommend prefinishing instead, especially
if you plan on a two-color finish.
Finish all the exposed wood (especially
the trellis pieces) before assembly.
You'll save tons of time and wind up
with a crisper paint job.